Acute Aortic Syndrome: Acute Aortic Diseases in Hemodynamically Unstable Patients

Four distinct acute aortic diseases that may result in acute aortic syndrome (AAS) should be distinguished: aortic dissection, intramural aortic hematoma (IAH), penetrating aortic ulcer (PAU), and incomplete aortic dissection (corresponding to an aortic wall laceration without dissection of the media). Each of these entities has a clear pathophysiology, but IAH may evolve into a classic aortic dissection, and PAU is frequently associated with intramural hemorrhage and may occasionally constitute the entrance tear of a subsequent aortic dissection. Syncope, hypotension, and shock are warning signs, which are commonly indicative for exsanguination or cardiac tamponade related to the involvement of the ascending aorta. Acute management depends on the nature of the AAS and aortic segment involved: prompt surgery on the ascending aorta and conservative treatment or endovascular repair for the descending aorta. Echocardiography has a pivotal role in the assessment of AAS patients with hypotension or shock. Transesophageal echocardiography (TEE) is preferred since it has greater diagnostic accuracy, though it can be unsafe in nonintubated patients (risk of collapse in the case of tamponade or aortic rupture in the case of acute increases in aortic pressure). Transthoracic echocardiography should be performed first in nonintubated patients since the identification of hemopericardium with potential tamponade, aortic regurgitation, and enlarged ascending aorta allows prompt surgery to be undertaken. In this case, TEE should be performed in the operating room in an anesthetized patient to refine the diagnosis of complicated AAS.associated with intramural hemorrhage and may occasionally constitute the entrance tear of a subsequent aortic dissection. Syncope, hypotension, and shock are warning signs, which are commonly indicative for exsanguination or cardiac tamponade related to the involvement of the ascending aorta. Acute management depends on the nature of the AAS and aortic segment involved: prompt surgery on the ascending aorta and conservative treatment or endovascular repair for the descending aorta. Echocardiography has diagnostic capabilities equivalent. Transesophageal echocardiography (TEE) is preferred, though it can be dangerous in nonintubated patients (risk of collapse in the case of tamponade or aortic rupture in the case of acute increases in aortic pressure). Transthoracic echo should be performed first in nonintubated patients since the identification of hemopericardium with potential tamponade, aortic regurgitation, and enlarged ascending aorta allows prompt surgery to be undertaken. In this case, TEE should be performed in the operating room in an anesthetized patient to refine the diagnosis of complicated AAS.